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Biomedical subjects

J Feldman

Publications and source records attributed to J Feldman.

At least 19 recordsLinked to original sources
PubMed1992

Oronasal reconstruction with local mucoperiosteal and free latissimus dorsi flaps.

We describe the use of maxillary sinus mucoperiosteum as a pedicled flap to reconstruct the floor of the nose following resection of cancer involving the palate, buccal mucosa, and mandible. Complete inferior turbinectomy allows access to the roof of the maxillary sinus to harvest the mucoperiosteum as a vascularized flap pedicled under the remaining middle turbinate. A free latissimus dorsi myocutaneous flap suspended from the floor of the orbit and nasal septum is then used to obliterate the maxillary sinus, reconstruct the palate, and support the floor of the nose. A reconstruction employing this combination of flaps is presented, including postoperative endoscopic intranasal photography and magnetic resonance imaging. Despite the elevated level of the floor of the nose and the absence of the inferior turbinates, rhinomanometry performed 3 months postoperatively demonstrates adequate nasal airflow with normal responses to nasal decongestants.

Aged↗
PubMed1992

Arthritis and hypertension in patients with systemic lupus erythematosus.

OBJECTIVE: The purpose of this study was to test the hypothesis that patients with systemic lupus erythematosus (SLE) who have, as part of their disease, persistent rheumatoid-like arthritis are less likely to be hypertensive than are other patients with SLE. METHODS: A retrospective chart analysis of 662 patients with SLE seen in a university clinic was performed. RESULTS: Data analysis revealed that hypertension and persistent arthritis were inversely correlated, particularly in those patients without nephritis and particularly in black patients. CONCLUSION: We conclude that rheumatoid-like arthritis in patients with SLE is protective against hypertension, and speculate that this protection is conferred by a higher frequency of the DR4 allele.

Arthritis↗
PubMed1992

Contribution of catecholaminergic neurons of the dorsomedial and ventrolateral medulla oblongata to the hypotensive effect of clonidine in spontaneously hypertensive rats: in vivo voltammetric studies.

OBJECTIVE: Our previous electrochemical studies in the normotensive Wistar-Kyoto (WKY) rat showed a positive correlation between the hypotensive effect of low doses of clonidine (2-10 micrograms/kg intravenously) and inhibition of the activity of catecholaminergic neurons within the brainstem, and that this action was mediated by imidazoline-preferring receptors. In the present study the possibility of a relationship between the centrally mediated hypotensive effect of clonidine and the metabolic activity of catecholaminergic neurons of the ventrolateral and dorsomedial medulla oblongata was investigated in pentobarbital-anaesthetized spontaneously hypertensive rats (SHR). DESIGN AND METHODS: Neuronal metabolic activity was monitored by in vivo electrochemistry in the nucleus reticularis lateralis region of the ventrolateral medulla and in the nucleus tractus solitarii region of the dorsomedial medulla oblongata. RESULTS: Hypotensive doses of intravenously administered clonidine (10 micrograms/kg) failed to inhibit the neuronal metabolic activity of the nucleus reticularis lateralis region; fivefold higher doses were required to inhibit these neurons. The low dose of clonidine (10 micrograms/kg) decreased the metabolic activity of the nucleus tractus solitarii region. Nevertheless, this effect did not appear to be correlated with a reduction in blood pressure and it was not attenuated by a prior central injection of idazoxan (5 nmol/kg intracisternally), which almost completely prevented the hypotensive and the neuronal inhibitory effects of clonidine in the nucleus reticularis lateralis region of the normotensive rat. CONCLUSION: Both the site and the mechanism of the central hypotensive action of clonidine in the SHR appear to be different from those in normotensive control WKY rats.

Animals↗
PubMed1992

[Pharmacology of imidazoline receptors and cardiovascular regulation. Imidazoline receptors and blood pressure].

To explain the central hypotensive action of clonidine- and rilmenidine-type drugs, a recent hypothesis suggested the involvement of imidazoline preferring receptors (IPR) insensitive to catecholamines. Binding studies performed on neuronal membranes prepared from the human Nucleus Reticularis Lateralis area (NRL) showed that rilmenidine was twice as selective as clonidine for the medullary IPRs. Voltammetric experiments revealed that these substances preferentially inhibited the activity of catecholaminergic neurones within the NRL, privileged site for their hypotensive action, rather than the activity of the neurones of the Locus Coeruleus (LC) where these drugs induce their sedative effect. The mechanism of the inhibitory action of these compounds upon the neurones of the NRL definitely involved IPRs when the inhibition of the LC neurones involved classical alpha-2-adrenoceptors. These functional studies also showed that rilmenidine exhibited a selectivity twice as important as clonidine, the reference substance. Poly- and monoclonal anticlonidine antibodies cross-reacting only with imidazolines allowed to detect and immunoreactive substance in the human serum. The amounts of that substance thus measured were higher in some hypertensive patients than in normotensive subjects. The identity of that immunoreactive substance with "endazoline", the endogenous ligand of the IPRs, is presently analysed.

Animals↗
PubMed1992

Imidazoline receptors. A new concept in central regulation of the arterial blood pressure.

Clonidine-like antihypertensive substances bind to nonadrenergic imidazoline specific sites within the nucleus reticularis lateralis (NRL), their medullary privileged site of action. Rilmenidine, a new central antihypertensive agent, was tested in the anesthetized rabbit. For the same hypotensive effect, cumulative doses given intracisternally proved 50 times more active than of those given systemically. Idazoxan, an alpha 2-adrenergic antagonist structurally related to the imidazolines, given centrally as pretreatment proved more potent in preventing the hypotensive effects than the same molar dose of yohimbine. When injected within the NRL area of the anesthetized rabbit, rilmenidine, like clonidine, always exhibited a hypotensive effect. The influence of clonidine and rilmenidine upon the NRL noradrenergic neurons involved in the blood pressure regulation, and upon those of the locus coeruleus (LC) involved in the sedative effect was studied by differential voltammetry. It was observed that rilmenidine was two times more selective than clonidine in inhibiting the NRL, as opposed to LC, neuronal activity. In addition, binding experiments of tritiated clonidine to human cortical and NRL membrane preparations showed that rilmenidine, as compared to clonidine, has a two to three times higher selectivity for the imidazoline receptors. In conclusion, we are now able to discriminate between the mechanism of the hypotensive effect of imidazoline-like drugs and that of their sedative action. Rilmenidine is the first example of an hypotensive drug more selective for imidazolin preferring receptors than for classical alpha 2-adrenoceptors.

Adrenergic alpha-Agonists↗
PubMed1992

The French are different. French and American medicine in the context of AIDS.

Medicine has often been approached as a thing apart from culture, as a uniform Western science. Within the past 10 years, we have begun to recognize that medicine is a system of beliefs and practices intrinsically linked to its larger sociocultural context. Still, it is generally perceived as uniform across North America and Western Europe. My recent research on French and American medical perspectives on the acquired immunodeficiency syndrome (AIDS) challenges this view by exploring differences in the structure of health care, the physician-patient relationship, and the conceptualizations of disease, particularly AIDS. These differences are not specific to AIDS, but the disease serves to exemplify them and to act as a medium for expressing what makes French and American medicine distinct. Global epidemics such as AIDS require both international response and cross-cultural understanding.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Predictors of cocaine use in pregnancy.

Several hundred thousand infants are exposed to cocaine in utero every year in the United States. In an attempt to provide services for women abusing drugs, various programs have been proposed for prenatal drug testing. This study was conducted to assess the sensitivity, specificity, and predictive values of screening programs based on a variety of clinical and historical factors. Between October 1988 and March 1989, 1111 parturients who delivered at an inner-city hospital had urine samples and data collected. The urine, linked by code number to the data, which contained no identifiers, was tested anonymously for illicit drugs. We then assessed the associations of a variety of historical and clinical variables with positive toxicologies. An acknowledged history of drug use or a combination of no prenatal care and cigarette use provided the most valid prediction of cocaine use, with a 59.8% sensitivity, 97.5% specificity, 70% positive predictive value, and 94.9% negative predictive value for positive urine toxicologic examinations. The addition of clinical data such as low birth weight did not improve predictive values significantly. Although the use of easily available historical data allowed correct identification of 60% of parturients who used cocaine, no combination of factors could detect all users. If it is considered beneficial to identify all users at a given point, then urine toxicology screening would be more appropriate than sole reliance on patient history.

Cocaine↗
PubMed1991

Selectivity of rilmenidine for the nucleus reticularis lateralis, a ventrolateral medullary structure containing imidazoline-preferring receptors.

Neuronal metabolic activity was studied by in vivo electrochemistry in two brain areas of the anesthetized rat: the nucleus reticularis lateralis (NRL) region of the ventrolateral medulla oblongata - site of the hypotensive action of clonidine-like imidazolines - and the locus coeruleus (LC), which is involved in the sedative effect of these drugs. Hypotensive doses of i.v. rilmenidine (0.3 and 1.5 mg/kg), which is structurally related to clonidine, induced a dose-related inhibition of the metabolic activity of catecholaminergic neurons in the NRL region whereas higher doses (50-fold) were required to inhibit the activity of the catecholaminergic neurons in the locus coeruleus. On the other hand azepexole, another centrally acting antihypertensive drug that is not structurally related to the imidazolines failed to inhibit the neuronal metabolic activity of the NRL region when administered i.v. in hypotensive doses (1 mg/kg). Taken together, these findings suggest that the central hypotensive action of clonidine-like drugs requires the imidazoline structure or pharmacologically compatible compounds like rilmenidine. Our results also show that rilmenidine is twice as selective as clonidine for the NRL region, which contains imidazoline-preferring receptors, compared with the LC, which contains mainly alpha 2-adrenoceptors. In conclusion, this study provides a functional confirmation of the dissociation between the therapeutic (hypotensive) and untoward (sedative) effects of rilmenidine.

Adrenergic alpha-Agonists↗
PubMed1991

Integration of form across saccadic eye movements.

To perceive a stable world, one must somehow be able to relate visual information from successive fixations. Little is known, however, about the nature of the integrative process. By using a task which requires the integration of spatial position information from different fixations, it is demonstrated that visual information from previous fixations is preserved in a world-centered representation which is precise enough to support judgements of geometric shape. It is also shown that successive views are aligned with respect to common visual features, indicating that visual stability may be normally accomplished by a visual matching strategy in combination with cancellation by an eye-position signal.

Attention↗
PubMed1991

An imidazoline-specific mechanism for the hypotensive effect of clonidine: a study with yohimbine and idazoxan.

Our previous in vivo electrochemical studies in the normotensive rat have shown that there was a positive correlation between the hypotensive effect of low doses of clonidine (8-40 nmol/kg i.v.) and the inhibition of the metabolic activity of catecholaminergic neurons within the nucleus reticularis region in the brain stem. Higher doses of the drug (200 nmol/kg i.v.) were required to decrease the metabolic activity in the locus ceruleus, which is involved in the sedative effect of clonidine. To investigate further the pharmacological mechanism involved in the hypotensive effect of imidazolines, low doses of antagonists were injected centrally in the cisterna magna (5 nmol/kg intracisternal): idazoxan, an imidazoline that labels nonadrenergic imidazoline-preferring sites and yohimbine, which is a classical alpha-2 adrenergic antagonist. Our results show that idazoxan very potently antagonizes both the hypotensive effect of clonidine and neuronal inhibition on the nucleus reticularis lateralis region but not in the locus ceruleus. The opposite effect is observed with yohimbine, i.e., neither the hypotensive effect nor the neuronal inhibition produced by clonidine on the nucleus reticularis lateralis region were affected but it prevented the inhibitory effect of clonidine on locus ceruleus neuronal metabolic activity. In conclusion, we confirm the hypothesis that the hypotensive action of imidazoline is due to an interaction of these substances with imidazoline-preferring receptors in the ventrolateral medulla oblongata whereas its sedative effect is related to an action on alpha-2 adrenoceptors.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Laparoscopic pelvic lymphadenectomy.

Eleven male patients with pelvic malignancy underwent laparoscopic lymphadenectomy for staging of their tumors. The technique allowed removal of pelvic lymph nodes in all 11 patients and metastatic disease was found in five cases, resulting in a change of recommended therapy. The technique was via a three-port exposure, although a fourth suprapubic port was occasionally used for additional retraction. A bladder laceration, which was repaired laparoscopically, was the only intraoperative complication. A pelvic hematoma was the only significant postoperative complication. Laparoscopic pelvic lymphadenectomy appears to offer a less morbid staging for those patients with a high likelihood of nodal metastasis. Laparoscopic detection of positive pelvic lymph nodes may alter the management of genitourinary malignancy and improve overall patient care.

Acid Phosphatase↗
PubMed1991

Passive smoking alters lipid profiles in adolescents.

Although cigarette smoking is associated with elevation of plasma lipid levels and changes in lipoprotein distribution, it is not known whether passive smoking is associated with an alteration in lipid profiles. The relation between plasma cotinine, a marker of exposure to tobacco smoke, and lipid profiles was studied in healthy adolescents from a suburban New York high school district who were undergoing preparticipation sports physicals. Forty-four percent of the adolescents reported that one or both parents currently smoked. Eleven percent of the adolescents had plasma cotinine concentrations greater than or equal to 2.5 ng/mL, the level considered indicative of exposure. Adolescents with two smoking parents had significantly higher plasma cotinine concentrations after adjustment for other factors than adolescents whose parents did not smoke. Plasma cotinine concentration greater than or equal to 2.5 ng/mL was associated with an 8.9% greater ratio of total cholesterol to high-density lipoprotein cholesterol (P less than .003) and a 6.8% lower high-density lipoprotein cholesterol (P less than .03). These results suggest that passive smoking, like active smoking, leads to alterations in lipid profiles predictive of an increased risk of atherosclerosis.

Adolescent↗
PubMed1979

Panoramic viewing, visual acuity of the deviating eye, and anomalous retinal correspondence in the intermittent exotrope of the divergence excess type.

Monocular visual acuities in a binocular field of view, field of view under binocular conditions, and retinal correspondence were investigated in five intermittent exotropes of the divergence excess type. Results indicated that all five intermittent exotropes demonstrated (1) normal visual acuity in the deviating eye without suppressing the fixating eye, (2) a lateral extension of the temporal field of view (panoramic viewing), (3) anomalous retinal correspondence.

Adolescent↗
PubMed1979

Maximal expiratory flows after postural drainage.

Flows measured from maximal expiratory flow-volume (MEFV) curves were used to evaluate the efficacy of postural drainage in improving ventilatory function acutely. Maximal expiratory flow-volume curves were obtained for 9 cystic fibrosis subjects and 10 subjects with chronic bronchitis before and 5, 15, and 45 min after a 30-min session of postural drainage with percussion, vibration, and coughing. Forced vital capacity (FVC) was significantly increased 45 min after drainage for the combining group. Flows at high lung volumes were different for the 2 subgroups. Subjects with cystic fibrosis demonstrated a significant increase in peak expiratory flow rates 45 min after drainage and an increase in forced expiratory volume in one sec at all time intervals. The subjects with chronic bronchitis had a decreased peak expiratory flow rate 5 min after drainage, but by 45 min, it had returned to baseline. There was no significant change in one-sec forced expiratory volume at any time interval for the chronic bronchitis subgroup. Changes in flows at low lung volumes were similar for the 2 subgroups. Forty-five min after drainage there was an increase in flow rates near 50 per cent of FVC. Flows near 25 per cent of FVC were increased 15 and 45 min after drainage. This study demonstrated that postural drainage with coughing resulted in significant improvement in flows at low lung volumes. Changes in flows at high lung volumes were less consistent.

Adolescent↗
PubMed1979

Adult mental health services in a health maintenance organization.

The authors describe an adult mental health service within a health maintenance organization and present information on the department's setting, staffing patterns, programs, and philosophy. They believe that the emphasis on brief focal psychotherapy, the staff of mental health care providers who are committed to this type of setting, and the thorough integration of the program into the larger HMO system all contribute to the provision of high-quality services at a reasonable cost.

Boston↗
PubMed1979

Assessing the Frisby Stereo Test under monocular viewing conditions.

A new random dot stereoscopic test, the Frisby Stereo Test, was evaluated to determine whether monocular information may be used in making correct responses. The performance of 34 optometry students was assessed under both monocular and binocular viewing conditions. Results indicated that one student was able to pass the test upon the initial monocular presentation. Two additional students were able to pass the test monocularly following binocular exposure. It was concluded that the Frisby Stereo test is about as effective as any other commercially available RDS test when used with adults. However, it may have potential deficiencies when used with children.

Adult↗
PubMed1979

Comparing stereoscopic performance of children using the Titmus, TNO, and Randot stereo tests.

The stereo acuities of 112 children between 3 and 11 years of age were assessed using the Titmus, TNO, and Randot stereo acuity tests. Results indicated that stereo acuity test scores improved with age and that performance variability decreased with age. Normal adult findings were achieved by age 7. Generally the Randot Stereo test yielded the best stereo acuity performances. It was concluded that the Randot stereo test is a better clinical test for use with children than either the Titmus or TNO stereo tests.

Age Factors↗